Forbidden
by muggle405
Summary: Because falling in love with your brother's best friend was just as forbidden as falling in love with your best friend's sister. Asucaga Oneshot. AU.


**Disclaimer: I do not own Gundam SEED/Gundam SEED Destiny or any of the characters used in this story. I also own none of the songs mentioned.**

**This is an Asucaga story, I promise. Don't let part of it fool you before you get to the end.**

"Guess who just got asked to prom!"

That was Miriallia's greeting to her best friend as she set her tray down on the lunch table and plopped down in the seat across from her, grinning all the while.

"Hm...I don't know.." Cagalli glanced around the lunchroom. "Lunamaria?" she guessed when she spotted the girl in question. As usual, the Hawke sisters' table was piled high with gifts from the elder's many admirers.

"No...Well, yeah, she probably did just get asked again, but that's not who I meant."

"I don't know why she won't just pick someone and put the rest of those guys out of their misery."

"What are we talking about?" Lacus interrupted as she took her usual seat next to Cagalli.

"Why Lunamaria can't just decide who to go with prom with already. There's not even a week left." Cagalli answered, pushing her food around her plate with her fork as she watched yet another poor boy try his luck.

"Actually, I was _trying_ to get her to guess who just got asked to prom."

"You?" Lacus knew she'd gotten the right answer when color crept up Miriallia's cheeks. "Well, who is he and what did you say?"

"Dearka Elsman. And I said yes."

"That's great, Mir. I have English class with him. He's a really nice guy."

"What about you, Cagalli? Who are you going with?"

The girl in question didn't hear the question at first, having been distracted by the sight of her twin brother entering the cafeteria with his best friend. And that's why she nearly jumped out her seat when Miriallia reached across the table to tap her on the shoulder.

"Hello? Earth to Cagalli. I asked who you're going to prom with." Miriallia prompted with a laugh.

"Hm? Oh..I'm not going."

"What? Why not?"

"Well, I mean it's not like I have anyone to go with. And you both know how I feel about dresses."

"You should just ask him." Lacus cut in, nodding towards Athrun who was standing in line with Kira.

"What? No. I can't do that. He's my brother's best friend. Do you know how awkward that would be?"

Miriallia couldn't help but laugh at that logic. "I'd like to point out that Kira is dating one of your best friends. Doesn't that amount to pretty much the same thing?" She looked at Lacus, who nodded in agreement.

"Well, yeah..I know...But it just seems like asking out my brother's best friend is like forbidden territory or something, y'know? I mean, the only time I ever get to talk to him is when he comes over to hang out with Kira. For all I know, he probably just sees me as a sister." Cagalli sighed.

"Aw, come on, Cagalli...You_ have _to go to prom. Lacus and I are both going."

"First, I don't _have_ to do anything. Second, I don't even have a dress."

"You can borrow one of mine. " Lacus offered. "I have plenty."

"See? Problem solved." said Miriallia, looking rather smug over the fact.

Cagalli sighed and looked down at her tray. "I don't know, you guys..." When she looked back up it was to see both Lacus and Miriallia giving her the puppy dog pout. "Ok. Fine. I'll go. But only if someone asks me."

Lacus glanced at Mir before shrugging. "Sounds fair enough."

"I'm glad it meets with your approval." Cagalli said, voice dripping with sarcasm. "Anyway, I need to get to the library. I've got a chemistry exam to study for."

She was already gone by the time Kira and Athrun arrived at the table.

Kira bent to give Lacus a kiss on the cheek before taking Cagalli's vacated seat.

"Where's Cagalli? Wasn't she just here?" Athrun asked as he, too, sat down.

Miriallia's eyes met Lacus's across the table and they both laughed.

Those two really were transparent when it came to their feelings for the other. Unfortunately, they were also both clueless.

* * *

"So who are you taking to prom?"

"Huh?" Athrun looked up at Kira from the algebra problem he was solving. The two were sitting at the counter in the kitchen at Kira's house, working on their math homework and the question had come out of the blue.

"You heard me."

Athrun dropped his pencil down onto his notebook and leaned back in his chair, flexing his hand to get rid of the writing cramp from working out so many math problems already. "I don't know...I haven't given it much thought I guess."

That was a lie. If anything, Athrun had given it too much thought. He really wanted to ask Cagalli to go with him, but was sure Kira wouldn't approve, so he hadn't said anything.

"Prom is in three days. You'd better ask someone soon if you don't want to go alone."

"Yeah. I know." he reached over to pick up his can of Dr. Pepper and take a drink of it.

"If you can talk her into actually going to a school dance, you could take Cagalli." Kira suggested.

Athrun nearly choked and it took a minute before he could reply. "You mean that wouldn't bother you?"

"Sure." Kira shrugged. "It's just prom, right?"

"Alright...Maybe I will ask her." He couldn't help but smile as he went back to working on their algebra assignment, though he wasn't really paying attention to the problems anymore.

Cagalli entered the house shortly after. They heard her come in through the front door and drop her bag and school books onto the couch before she entered the kitchen.

"Hey, guys. What are you working on?" She leaned over Athrun's shoulder to see what page the book was open to. "Ugh...Parabolas. I hate those." That wasn't saying much since Cagalli hated all math problems.

She made her way to the refrigerator and began moving things around, obviously looking for something. Having just come from practice, she was still wearing her soccer team uniform and had her hair pulled back in a ponytail, but Athrun always thought that was when she was most beautiful.

She straightened after a moment, holding a bottle of gatorade, and turned to face the two, only to find them having a silent conversation with each other across the counter. She raised and eyebrow and shut the refrigerator door.

Kira seemed to win the silent argument and Athrun turned to face her. "Uh..Cagalli, could I talk to you about something?"

Cagalli would have been lying if she said her curiousity wasn't piqued at that point. She twisted the cap off of her gatorade as she came over to sit with them. "Yeah, sure. What is it?"

* * *

Lacus answered her cell phone on the second ring. "Hey, Cagalli. What's up?"

"...Athrun just asked me to prom."

"That's great!" Lacus was genuinely happy for her friend, though found it odd that Cagalli didn't sound more excited about it.

There was a long silence while neither of them said anything before Lacus continued, "Why do you sound less than thrilled?"

"Because I already had a date to prom by then."

_Flashback_

_"I was just wondering if...maybe you'd like to go to prom with me?" Athrun asked after a pause._

_Cagalli was silent for a moment. She wanted to say yes, she really did, but she'd already agreed to go with someone else not even half an hour ago. "I'm really sorry, Athrun, but I already have a date."_

_"What? Who?" This outburst was from Kira. When both Cagalli and Athrun looked at him, he went silent. "Sorry..None of my business. Got it."_

_"It's Yuna Roma Seiran. He's on the student council with Lacus. I ran into him on my way home from soccer practice and he asked me. With prom only three days away, I figured no one else would ask me, and Miriallia and Lacus have been bothering me about going to prom with them, so I said yes."_

_Athrun forced a smile and shrugged. "It's fine. It was just a thought."_

_End Flashback_

_

* * *

_

The last few days before prom passed by quickly.

As student body president, Lacus was kept busy overseeing the various committees as they put together the finishing touches on everything. The band had been selected and hired, the ballroom of a local convention center rented for the evening, and the decorations put up.

Cagalli thought Lacus had done a wonderful job organizing everything as she looked around the ballroom on prom night. She marvelled at how, despite the fact that she'd been nearly run ragged trying to get everything done on time, Lacus had still found time to help Cagalli find a dress for the evening, a lovely light blue silk evening gown. She had refused point blank to wear anything like Lacus's pale pink strapless ballgown.

Thought Cagalli was still disappointed that she hadn't been able to attend prom with Athrun, she was trying to make the best of the evening. Yuna had picked her up from her house two hours before the dance would start and taken her to dinner at a local Italian restaurant. He'd been with her up until a moment before when he'd gone to speak with one of the band members.

She was in the process of scanning the crowd for Athrun when Miriallia approached her from behind and tapped her on the shoulder. She was flushed from dancing, but alone.

"Where's your date?" Cagalli asked curiously.

Miriallia nodded towards the refreshment table. "Getting us both something to drink. It's really hot in here. Yours?"

"Over there."

But Miriallia didn't look to see where Cagalli was pointing. Instead, she was staring at the entrance, apparently surprised by something she saw there. When Cagalli turned to look, Miriallia stopped her.

"Don't look now, but I know why Lunamaria wouldn't make a decision now."

Of course, Cagalli had to look at that point only to see the girl in question entering on the arm of her date, Athrun. She was too stunned to react for a moment. No one had seen that one coming. She was brought out of her thoughts by the sound of Dearka's voice. He'd apparently returned from the refreshments table sometime in the past few minutes and given Miriallia the bottle of water she'd asked for.

"You ready to go dance some more, babe?" he asked, one arm draped around Mir's shoulders.

Miriallia grinned up at her date and nodded. She glanced back at Cagalli over her shoulder as she was led away towards the dance floor. "I'll catch up to you later, okay?"

Cagalli nodded numbly, watching her friend disappear into the crowd. She glanced back over at Athrun and Luna again before quickly looking away again. She forced a smile when she saw Yuna coming back towards her.

When he got closer, he held out his hand to her. "Want to dance?"

Cagalli took his hand and let him lead her out to the dance floor just as the song changed to Elton John's _Tiny Dancer_.

"You like this song, right? I asked the band to play it."

"Yes, it's one of my favorites, but how did you know?"

"You paused your Ipod when I came up to talk to you the other day, but I could still see the name of the song on the screen." He was obviously pretty proud of himself for noticing such a small detail.

Cagalli let him put his hands on her waist as they danced in time with the music. It felt odd to be held by another man when the one she really loved was off somewhere in the same room, probably dancing with his date in much the same way. She pushed the thought from her mind, trying to enjoy herself for at least a little while. Just because she hadn't wanted to come to prom to begin with, she wasn't going to sulk the entire time. That wouldn't be fair to her date, since obviously he was interested in her enough to ask her to prom, even if he had waited so long to do it.

Now if only she could ignore the fact that he kept trying to move his hand lower while the danced.

As they danced, Cagalli couldn't help but think, _why couldn't Athrun have asked me first?_

* * *

From where he was dancing with Lunamaria, Athrun could see Cagalli with Yuna and he hated every minute of it. He couldn't help but think that that should have been him dancing with her. He knew the song was one of her favorites.

If only he had asked her sooner.

He didn't feel guilty for thinking about Cagalli so much while he was dancing with Luna, not in the least.

She had been the one to ask him, though he wasn't supposed to tell anyone that. She'd picked him above all of the other guys who had been asking her for weeks because she thought he would be best suited for her purposes.

She was trying to make her ex-boyfriend, Shinn Asuka, jealous. She'd told him so herself.

Going off of the death glares he'd been receiving from Shinn since they walked in, Athrun would wager she'd succeeded. Well, good for her. At least one of them had accomplished something.

* * *

As the band finished the song, the crowd fell silent.

Lacus had just taken the stage and everyone knew what that meant.

One of the band members handed her a microphone and Lacus waited for the spotlight to come on before she began to speak.

"Thank you to everyone who has worked so hard to make this night a reality. You did a wonderful job."

There was a slight smattering of applause for the prom committee before she continued.

"And now for the moment you've all been waiting for. Time to announce this years Prom King and Queen." She accepted the envelope with the results from the school's principal, Ms. Murrue Ramius, "And the King and Queen are..." she pulled the card from the envelope and grinned, "Athrun Zala and Cagalli Yula Attha!"

Cagalli was too stunned to react. It made no sense. She'd expected it to be Lunamaria, but then maybe the girl had made a few too many enemies when she'd monopolized the majority of the male population of their highschool with her reluctance to pick one. That could have lost her votes.

Athrun had already made it to the front of the dance floor and Lacus was coming down to put the crown on him when Kira, who had come to stand with Cagalli while his girlfriend was up on stage, gave her a small shove towards the stage.

Cagalli was still having a hard time believing it, even after Lacus had placed the tiara on her head and asked everyone to clear the floor for the King and Queen's dance.

The band struck up_ You and Me _by Lifehouse as Athrun led her out onto the dance floor. "It looks like I get to dance with you after all. You could at least try to look happy about it." he teased as he turned to face her and held out his arms.

"I am...just a little shocked I guess." she replied as she stepped into his arms. She turned her head to the side, hoping he wouldn't notice her blush.

"Why? I voted for you."

Cagalli looked up at him at that point. "You did? Why?"

It was Athrun's turn to be embarassed. "Er...Well...I thought you deserved it."

They both fell silent after that, lost in their own thoughts.

All too soon, the song ended and they stepped away from each other.

"I'll..uh..talk to you later." Cagalli said awkwardly before turning to go back to her date before Athrun could notice her blush.

He frowned as he watched her disappear into the crowd. He stared after her a moment longer before turning to go back to his own date.

* * *

"Well, aren't I the lucky one?" Yuna joked as she rejoined him. "I get to be with the prom queen."

Cagalli forced a laugh.

When the next song started, he gathered her a bit closer than she would have liked as they danced. After a moment, he bent his head down to whisper, "What do you say we go ahead and get out of here? Head back to the hotel?"

"What?" Cagalli pushed away from him instantly. When he just continued to look at her, expecting an answer, she demanded, "Is that why you asked me to come with you?"

"Well, yeah...It's prom night. What'd you think?"

* * *

Kira heard the slap all the way across the room. He saw his sister rushing out towards the balcony and moved to go after her to make sure she was okay before Lacus put a hand on his arm to detain him.

"Let Athrun take care of it." she said.

Sure enough, Athrun was already following her out onto the balcony, not far behind.

* * *

"Cagalli? Are you alright?" he asked as he stepped out onto the balcony after her.

She had her back to the door, her arms resting on the railing as she stared out over the city. "Yeah. I'm fine." She lifted one hand to wipe the back of it under her eyes.

The night air was rather chilly, which accounted for why no one else was on the balcony anymore. Athrun slipped off his tuxedo jacket as he approached her and draped it carefully over her shoulders as he came up beside her.

"Really? You don't sound fine." Using one finger, he gently wiped a tear from her cheek.

"You should go back to your date. She's probably wondering where you are."

"She'll be fine. I don't think she misses me."

Following his gaze, Cagalli saw Luna dancing with Shinn. "Her loss." she joked, trying to wipe away the rest of her tears.

"So, do you want to talk about it?"

Everything was silent for a moment, the only sound the faint music of the band drifting out through the open balcony doors. It was Edwin McCain's _I'll Be_, another one of her favorite songs.

"No? How about a dance then?" And he held out his arms for her.

Cagalli smiled and wrapped her arms around his neck. He always did know how to cheer her up. And so, they danced as if in their own world out on the balcony, her head resting against his chest.

After a moment, she began to speak. "I just...feel pretty stupid, I guess. I should have never agreed to go with someone I barely knew. I'd have much rather come with you." she admitted. "At least I know you wouldn't have tried to get me to go to a hotel room with you."

Athrun's hold on her tightened. "Is that what he did?"

She nodded. "Yeah..but it's fine. I can take care of myself."

"So I saw." The sound of that slap really had carried quite a ways, and over the volume of the music no less. "But, damnit, Cagalli, you deserve so much better than that. You deserve someone who will love and cherish you. Someone who will treat you like a princess."

She leaned back slightly to look up at him. She recognized the look he was giving her. It was the same way she always saw Kira look at Lacus. Now that she thought back on it, Athrun had always looked at her that way. "Will you be that someone?"

"If you'll let me." And without any further thought to whether or not Kira would kill him for it later, Athrun did somethign he'd wanted to do for a very long time. He bent his head down and pressed his lips firmly against hers.

Somewhere inside, Kira could be heard saying loudly: "Well, it's about time."

* * *

**This One-shot is a result of me being snowed in for three days straight.**

**I hope you enjoyed the story. If you liked this one, you might also like to read my other Asucaga fic, ****Once Upon A Time****.**

**Also, look up my GS/GSD amvs on youtube. My name is muggle405 there as well. **

**Let me know what you think!**


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